Krome Tan

I pulled out my old correspondence books from Northwestern School of Taxidermy the other day after skinning a squirrel. I thought my son and I might try our hand at tanning the hide, since I never completed the course. Krome tan seems to be the key, but where can I find it and how much does it cost? Does Bass Pro Shops or somewhere sell it? As I read some of these postings, it seems Northwestern is no longer around. Any help would be greatly appreciated. Thanks!